Synapse

Synapse is the Tyranid Psychic Power which unites all of the Tyranids into the Hive Mind. It is projected by Synapse Creatures which are usually leaders such as Hive Tyrants, Tyranid Warriors and Broodlord or specialist psykers like Zoanthropes. These creatures have greatly increased synapse networks within their cortex and these act as psychic conduits for the Hive Mind to order nearby troops. Without the Synapse guiding them, most Tyranids will revert to a feral state, although some, such as Genestealers with their Brood Telepathy, can perform just as well without Synapse as they do with it.[1][2]

Synapse Creatures

Synapse Creatures are some of the larger, more intelligent Tyranid organisms that act as psychic conduits or nodal relays through which a portion of the iron will of the Hive Mind flows to other lesser members of the hive. It is through Synapse that the swarms' natural Instinctive Behavior is overridden to the will of the Hive Mind.[Needs Citation]